Capsular polysaccharide synthesis, cell division and radiation sensitivity are controlled by the capR (lon) gene, as well as other genes in E. coli K-12. The overall objectives of the proposed research are: (a) to understand the mechanism of control of cell division at a molecular level as related to mutations in E. coli K-12 designated capR, sulA and sulB. The capR mutation causes sensitivity to UV, X-rays, ozone aad furadantin (a radiomemetric drug). After treatment with UV, capR mutants form nonseptate filaments that do not divide and will not produce a clone. Either mutation in sulA or sulB reverses the sensitivity of capR mutants to UV and furadantin. capR sulA, and sulB map in different regions of the E. Coli K-12 chromosome. (b) to understand how capR mutations also control, at the molecular level, synthesis of the enzymes of polysaccharide synthesis and overproduction of the capsular polysaccharide (with emphasis on the galETK operon). (c) to understand how our recently cloned genes specifying a major outer membrane protein and two other polypeptides (none of which are the capR gene product) control capsular polysaccharide synthesis in capR mutants. We have cloned the capRions gene on a tetracycline resistance plasmid and have identified and purified the capRions gene specified protein. It is a 92 kilodalton monomer that, in the native state, binds DNA nonspecifically and has ATPase activity. We are purifying the protein further and seeking other in vitro activities that it may have to determine how if functions in vivo. Similar techniques including bacteriophage cloning vectors, are being used to isolate the sulAions and sulBions genes and the proteins they specify. We have cloned a 2 x 10 to the 6th power dalton DNA fragment that controls capsular polysaccharide synthesis and three polypeptides that it specifies, including the major outer membrane polypeptide a, are needed to shut off capsular synthesis. We will purify them and determine their function(s) in vitro (repressor, protease, nuclease, etc.).